Pests and diseases

Pests and diseases can occur in backyard fruit trees. PlantNet uses the best rootstocks available for our varieties to minimise susceptibility of our trees to soil borne pests and diseases in the backyard.

Pests and diseases can quite often be localised to a particular area and are also dependent on each growing season.

If you see any pest or disease symptoms on your fruit tree, PlantNet recommends that you take a sample to your local nursery so they can assess it and advise you on the best treatment options. Remember that your local nursery is licensed to sell most chemical control treatments to help you solve your pest and disease issues but don’t forget there are also organic and eco-friendly treatments available.

We also recommend you join the Graham Ross’ Garden Clinic Club where you can access the Garden Clinic Help Line which has a qualified horticulturist ready to answer your questions.

The timing of pest and disease control is often linked to the tree dormancy and bud swell stages which are shown below.
Stone fruit dormant buds
Stone fruit bud swell
Apple dormant buds
Apple bud swell

Apples and pears

Alternaria Disease

Description

Early signs are purple lesions later turning to brown. More common in QLD.

Black Spot

Description

Shows as sunken black spots on the fruit surface, increasing as fruit grows.

Treatment

It is very important to maintain a healthy tree, to help prevent this disease taking hold. It is very important to plant trees where there is good air movement to minimise humidity. Fungal diseases will thrive in higher humidity.

As with apple scab, it is important to do one copper oxychloride or copper hydroxide spray as soon as trees lose their leaves in the winter.

Control of apple scab and Alternaria disease through summertime can be achieved by using Mancozeb fungicide.

Many home remedies have limited success in treating fungal diseases but it is worth checking the links mentioned above.

Apple Scab

Description

Young leaves show infection as velvety green spores that turn black with as the fruit ripens.

Treatment

Remove all leaves from around tree after leaf fall. Use the same information as for Alternaria control.

Apple Dimpling Bug

Description

Greenish/Brown, 3mm long. Damage is seen as small dimpling on the fruit skin.

Treatment

Spray 10g of soap in 1L of water every 3 days during pink flowering to petal fall and early fruit set (all states).

Adult bug
Damage from bug

Codling Moth Larvae

Description

Adults are grey/brown, wing span 12-19mm. Larvae have a black head and are 10-15mm long. Damage can occur from fruit set to fruit harvest, showing as small holes on the fruit surface.

Treatment

Pheromone traps can be used to reduce number of moths (refer to PlantNet traps for instructions). If damage exceeds 3%, then spray with biological products such as Spinosad.

Light Brown Apple Moth

Description

Young larvae are pale and 1-2mm long, it is rare to see the adult moth. Damage can occur from fruit set to harvest and shows as small holes on the fruit surface.

Treatment

Pheromone traps can be used to reduce male moths (refer to PlantNet traps for instructions). Always spray larvae when young for best results. If damage gets over 3%, spray with biological products such as Spinosad.

Links:
Bugs for Bugs

Queensland Fruit Fly

Description

Adult is red, brown and yellow.  Larvae are white maggots. Damage to the fruit is seen as sunken pin pricks slowly going soft as fruit matures. Damage may occur from early fruit maturity (QLD, NSW, VIC).

Treatment

Male attractant bait traps (Refer to PlantNet traps for instructions).

Apply protein bait to attract and kill male and female. (available from the PlantNet online shop.

Exclusion netting can also be used, no bigger than 3mm holes.

Queensland Fruit Fly Adult
Queensland Fruit Fly larvae

San Jose scale

Description

Adult female is yellow concealed by a grey/brown scale.  It attaches to bark and branches on trees and sometimes fruit.

Treatment

The best control is one application at dormancy of paraffin oil, Eco Oil (manufactured for horticulture) or a soap based product to smother scale.

The Chilocorus predatory ladybird will also control scale (see Bugs for Bugs).

Thrips

Treatment

It is important to treat the flowering stage. Try a natural remedy for moth larvae, mites and thrips: 100g chopped garlic, 2 tsp of vegetable oil, 2 tsp of dish washing detergent, 500ml of water.

Plague Thrips
Hard to see with the human eye. Adult female is about 1.1 to 1.3mm long and infests flowers.
Western Flower Thrips
Adult female is 1.4 to 1.8mm long and will start in the flower but will also damage young fruitlets.

Two Spotted Mites

Description

Small insects that sometimes can only be seen with a magnifying glass. Three species (Two Spotted Mite, European Red Mite, and Bryobia Mite)

Depending on where you are in Australia may depend on which species you have.  These insects damage the leaves of plants. Some of them are found underneath the leaf some on the upper surface of the leaf.

Damage is seen as discolouration of the leaf surface.

Treatment

The natural predator is persimilus mite. These can be purchased from predatory Insect breeders Biomites.

Mites can become uncontrollable if insecticides used for other pests are over used. Try a natural treatment of 100g of chopped garlic, 2 teaspoons of vegetable oil, 2 teaspoons of detergent in 500ml of water.

“Persimulus” two spotted mite predator. Available from Bugs for Bugs
Mite damage

Apricots, Nectarines, Peaches and Plums

Brown Rot

Description

Damage starts as a small grey to brown spot and as fruit matures it increases in size.

Treatment

Best control is a copper spray (copper hydroxide or copper oxychloride) at dormancy and 1 spray at bud swell. Apply Mancozeb during flowering to early fruit set (use the same program for Blossom Blight).

Codling Moth

Description

Larvae have a black head and are 10 to 15mm long. The adults are grey/brown with a wing span of 12 to19mm. Larvae have a black head and are 10 to 15mm long.

Damage can occur from fruit set to the harvest of fruit. Damage shows as small holes on the fruit surface to begin with and holes get bigger as the fruit grows.

Treatment

Pheromone traps can be used to reduce numbers of moths (refer to PlantNet traps for instructions).

Leaf Curl

Description

As new shoots come after dormancy, damage will show as curled and blistered leaves.

Treatment

Best control is a copper spray Kocide Blue (copper hydroxide) or copper oxychloride at leaf fall/dormancy and 1 spray before bud-swell. This is the only opportunity for control. Once trees break dormancy it is to late for control and spray damage may occur.

Fullers Rose Weavil

Description

Damage is seen as chewing of older fully expanded leaves and all stages of flower.

Treatment

Squash them!

Green and Black Peach Aphid

Description

Small insects 1.5 to 3mm long that manifest in flower buds and new growth. Damage may be seen as distorted growing tips.

Treatment

Try the mixture as per mites and thrips, but only if aphids are found.

Green Vegetable Bug

Description

Adult bugs suck fruit and leave a soft spot through to the seed. This will rot as fruit matures.

Treatment

Squash bugs when you see them (they are a member of the stink bug family so beware as you squash them as they will try and spray you with their defensive odour which…well stinks! Use gloves).

Monolepta Beetle (Red Shouldered leaf beetle)

Description

7mm long, yellow with a red spot on each wing, tend to travel in large numbers. At its worst in warmer humid climates. Damage is seen as fruit and leaves being chewed.

Treatment

Individual beetles can be squashed by hand if seen. Try the mixture as per mites and thrips, but only if Aphids are found. If swarms are found an insecticde like pyrethrum is the only answer.

Orange Fruit Borer

Description

Larvae are brown on top, light grey underneath, 20mm long with a dark brown head and brown stripes along the length of the body. Larvae chew and burrow into fruit.

Treatment

Try 100g of chopped garlic, 2 teaspoons of vegetable oil, 2tsp of detergent in 500ml of water.

Oriental Fruit Moth Larvae

Description

Small white larvae. Damage is seen on new growing tips where eggs are laid and larvae bore into the tip causing it to wilt and die.

Treatment

Pheromone traps can be used to reduce numbers of moths (refer to PlantNet traps for instructions). There is a few organic protectants available for use but timing of application of these is important. They must be applied at the egg stage or soon after the larvae hatch as once the larvae begin to grow they are not affected by many of these products.

Plague Thrips Damage

Description

Hard to see with the human eye.  Adult female is about 1.1-1.3mm long and infests flowers.

Treatment

It is important to treat the flowering stage. Try the mixture as for mites to control them (natural treatment of 100g of chopped garlic, 2 teaspoons of vegetable oil, 2 teaspoons of detergent in 500ml of water).

Queensland Fruit Fly

Description

Adult is red, brown and yellow.  Larvae are white maggots. Damage to the fruit is seen as sunken pin pricks slowly going soft as fruit matures. Damage may occur from early fruit maturity (QLD, NSW, VIC).

Treatment

Male attractant bait traps (Refer to PlantNet traps for instructions).

Apply protein bait to attract and kill male and female. (available from the PlantNet online shop)

Exclusion netting can also be used, no bigger than 3mm holes.(available from the PlantNet online shop)

San Jose scale

Description

Adult female is yellow concealed by a grey/brown scale.  It attaches to bark and branches on trees and sometimes fruit.

Treatment

The best control is one application at dormancy of paraffin oil, Eco Oil (manufactured for horticulture) or a soap based product to smother scale.

The Chilocorus predatory ladybird will also control scale (see Bugs for Bugs).

Rust

Description

Small yellow pin head sized spots on the upper leaf surface.

Treatment

Best control for Rust, Shot Hole and Curly Leaf is a copper spray (copper hydroxide or copper oxychloride) at leaf drop and at mid dormancy. Rust and Shot Hole can be controlled through summertime with Mancozeb fungicide.

Western Flower Thrips Damage

Description

Adult female is 1.4 to 1.8mm long and will damage the flowers, but will also damage young fruitlets.

Two Spotted Mites

Description

Small insects that sometimes can only be seen with a magnifying glass. Three species (Two Spotted Mite, European Red Mite, and Bryobia Mite)

Depending on where you are in Australia may depend on which species you have.  These insects damage the leaves of plants. Some of them are found underneath the leaf some on the upper surface of the leaf.

Damage is seen as discolouration of the leaf surface.

Treatment

The natural predator is persimilus mite. These can be purchased from predatory Insect breeders Bugs for Bugs.

Mites can become uncontrollable if insecticides used for other pests are over used. Try a natural treatment of 100g of chopped garlic, 2 teaspoons of vegetable oil, 2 teaspoons of detergent in 500ml of water.

“Persimulus” two spotted mite predator. Available from Bugs for Bugs.
Mite damage

White Peach Scale

Description

Much smaller than San Jose scale, almost like white dust on the trees bark when first seen. Can kill limbs on trees much quicker than San Jose scale.

Treatment

Control is one application at dormancy of paraffin oil, Eco Oil (manufactured for horticulture) or a soap based product to smother scale.

Chilocorus predatory ladybird will also control scale.

Citrus

Citrus Leaf Miner

Description

See the image here for description. The damage caused by this pest can stunt young trees growth and therefore must be controlled.

Treatment

Control in young trees by spraying spray eco oil or similar every two weeks on emerging new growth flushes. Once flushes have hardened off control can stop.

Citrus Stink Bug

Description Some years this insect is worse than other years. It stings the fruit which will either fall to the ground or become dry in the flesh around where it was stung. Beware – if disturbed or touched these insects sometimes spray a substance that stings the eyes severely. Treatment Some spray oils will kill the young insect stage but will not affect adults, so a destructive insecticide may be required.

Queensland Fruit Fly

Description

Adult is red, brown and yellow.  Larvae are white maggots. Damage to the fruit is seen as sunken pin pricks slowly going soft as fruit matures. Damage may occur from early fruit maturity (QLD/NSW).

Treatment

Male attractant bait traps (Refer to PlantNet traps for instructions).

Apply protein bait to attract and kill male and female. (available from the PlantNet online shop)

Exclusion netting can also be used, no bigger than 3mm holes.

Queensland Fruit Fly Adult

Blueberries

Blueberry Rust

Description

A fungal disease, most likely to be worst in wet or humid climates.  Spots are purple to brown in colour and round to angular in shape.

Treatment

We recommend Kocide Blue Fungicide as the most effective control for high disease pressure. Spray every 2- 3 weeks in wet or humid climates to protect plants from getting this disease as once it begins to spread it is very hard to control.

Blueberries do not have many pests but, if you are trying to identify pests please refer to pest images and information for other fruit trees above